42 percent of Windows Phone buyers came from feature phones, 25 percent from other Windows devices and 23 percent from Android.

"But it's not just about capturing the market that is yet to upgrade. Windows is also seeing success in the younger group. When looking at those who changed device, between 2011 and 2012 Windows was more successful at capturing older consumers aged 50-64. But when looking at those changing now and in the last year, we're seeing Windows now gaining share among those aged 25-34," said a Kantar analyst.